"This film married my two favorite things in the world: music and fashion," says Carol Beadle, who created the costumes for The Runaways, the much-anticipated biopic on Joan Jett and her titular proto-punk girl group. Beadle talked to us about evoking the late '70s, working with Kristen Stewart and Dakota Fanning (who play Jett and the band's bombshell lead singer, Cherie Currie, respectively), and how to put a contemporary spin on Jett's inimitable style.